feature #18398 [Workflow] Metadata dumping (Louis-Proffit)

This PR was submitted for the 6.3 branch but it was merged into the 6.4 branch instead.

Discussion
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[Workflow] Metadata dumping

Refs
* symfony/symfony#50604

Document metadata dumping option for workflow. The corresponding symfony PR handles only DOT dumper.

Commits
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3a4b436 [Workflow] feature symfony#50604 metadata dumping

Author: OskarStark

_images/components/workflow/blogpost_metadata.png

@@ -65,6 +65,21 @@ files and ``PlantUmlDumper`` to create the PlantUML files::
 Styling
 -------
 
+You can use ``--with-metadata`` option in the ``workflow:dump`` command to include places, transitions and
+workflow's metadata.
+
+The DOT image will look like this :
+
+.. image:: /_images/components/workflow/blogpost_metadata.png
+
+.. note::
+
+    The ``--with-metadata`` option only works for the DOT dumper for now.
+
+.. note::
+
+    The ``label`` metadata is not included in the dumped metadata, because it is used as a place's title.
+
 You can use ``metadata`` with the following keys to style the workflow:
 
 * for places: